Carbureting apparatus



June 13, 1950 J. H. LESLIE, It

CARBURETING APPARATUS 3 Sheets-Sheet 1 Filed April 26, 1945 June 13, 1950 J. H. LESLIE, 1I

CARBURETING APPARATUS 3 Sheets-Sheet 2 Filed April 26, 1945 June 13, 1950 .L H. LESLIE, 1I 2,511,213

CARBURETING APPARATUS Filed April ze, 1945 s shuts-sheet s lllllll VIII Illlll Maz/wsa Patented June 13, 1950 UNIT-Eo STATES` PATENT OFFICE.l

2,511,213 CARBURE'rmG APPARATUS John H. Leslie, 1I, Winnetka, lll., assigner to Stewart-Warner Corporation, Chicago, Ill., a A. corporation of Virginia Application April 26, 1945, Serial No. 590,379

' tions in the rate of engine air induction for controlling the rate at which the fuel is fed into the intake passage. f

Another object of the invention is to provide new and improved means for maintaining a substantially constant air pressure immediately adjacent the point of discharge of each of the nozzles.

A further object of the invention is to provide a new and improved fuel control valve with means responsive to variations in the pressure of the fuel supply to regulate the pressure at which the fuel is fed to the engine intake and to automatically vary the flowl of fuel in accordance with changes in the rate of engine air induction.

It is also an object of the invention to provide an internal combustion engine with an auxiliary air supply arranged to furnish a limited quantity of air to each of the engine cylinders independently of the throttle valve which controls the main air supply and to provide a space adjacent the intake passage of each cylinder and inl communication therewith to which the auxiliary air is furnished at substantially atmospheric pressure and into which space the fuel feeding nozzle extends so as to be subject to atmospheric pressure at all times in order to insure uniformity of operation of the fuel feeding means.

Other objects and advantages of the invention will appear from the following description taken in connection' with the drawings, in which: l

Fig. 1 fragmentary side elevation of a multiple cylinder internal combustion engine with the intake passage and air induction tube shown in section;

4 Claims. (C1. 261.-40)

In the fuel feeding and carbureting system to I which this invention relates, the liquid fuel is supplied by an engine driven pump and is re- V leased to the cylinders by a pressure control valve device which is responsive to variations of the air flow rate to the intake manifold, such varil ations being produced mainly by adjustment of the throttle valve and =by engine load and speed.

The liquid fuel is distributed from the control valve device to individual nozzles by which it is sprayed into the intake passage adjacent the inlet valve of each cylinder; but since -the pressure in the intake passages varies through wide limits in the course of operation of the engine, it is undesirable to have the outlet orifices of the i fuel nozzles subjected to these variations in pres- Fig. 2 is a fragmentary top plan view of the engine shown in Fig. l but with the air induction tube shown` in transverse section, as indicated at line 2-2 on Fig. l;

4Fig. 3 is a vertical detail section. taken suby stantially as indicated at line 3-3 on Fig. 1 but on a larger scale; L

Fig. 4 is a vertical detail sectional view of the sure. It is preferable to arrange the nozzles in such a way that they shall be subject to constant pressure at their discharge openings; then since the fuel is fed to the nozzles at variable pressures, depending upon the air flow rate, the rate of fuel supply can be proportioned properly to the air flow rate and will not be additionally altered -by other variable factors such as the pressure in the inlet manifold and intake passages. However, alteration of the proportions of fuel and air can still be effected intentionally, Iby use of the choke valve.

The drawings illustrate a multiple cylinder engine I0 having an exhaust manifold I2 which may be of conventional design and having an intake manifold I4 which is shown as provided with an air induction tube I6 connected into the middle of the length of the manifold I4 for distributing air to the several branch intake passages I8 each of which leads to one of the engine cylinders. The air induction tube has the usual Venturi form with its constriction at 20 and is fitted with a throttle valve 22.and a choke valve 24. The tube IB is shown surmounted by an air filter 26.

In addition to the air supplied by the induction tube I6 and intake manifold I4, the cylinders are furnished with a limited auxiliary air supply provided by auxiliary passages 28, 2B extending along opposite sides of the air induction tube I6 and continuing in passages 30, 30, each associated with a portion of the intake manifold I4 and each having branch passages 32 associated with the re- .i fuel feeding valve device being taken substantially a5 indicated at line l--I 0n Fig. 2.

spective intake passages I8- which lead to the several cylinders. The air intake ports 34 of the auxiliary passages 28 are-located adjacent the outer end of the induction tube I 6 beyond the choke 24 but in position to receive ltered air from the filter 26; and each of the branch passages 32 connects with the intake passage I8 by way of a port or orifice 38 which is preferably dimensioned to supply just enough air for idling the engine with the throttle valve 22 completely closed. The auxiliary passages 28, are thus open to atmospheric pressure at all times independently of the adjustment of the choke 24 or throttle 22 and a space in each of their branches 32 adjacent the port 3G is thus maintained constantly at substantially atmospheric pressure.

In addition to furnishing air for idling the engine, each of the ports serves for introduction of the liquid fuel into the air stream by reason of the fact that a fuel injection nozzle 3l is mounted in the top wall of each branch e 32 in position to discharge a jet or fine spray of fuel across the air gap indicated at 4l in Fig. 3 and directly through the port It into the intake passage Il, adjacent the inlet valve 42 of the engine cylinder. Since the discharge opening 44 of the nozzle Il is spaced back from the port It with the air gap interposed, the nozzle will be subject to the substantially uniform atmospheric pressure which is maintained in the auxiliary passage 32.

Fuel is supplied to each of the nozzles Il by a feed tube 4I having a T-fltting 48 into which the supply tube Il is coupled. The tube leads from a fuel control valve device denoted generally by the numeral l2 and shown in detail in Fig. 4. The device includes a lower casting 54 containing a fuel chamber 54 with a valve seat fitting 58 screwed into the bottom'of the chamber in the inlet passage thereof into which is connected the supply pipe 60 leading from .the engine driven pump 82 as shown in Fig. 1. 'I'he cast element 54 is surmounted by a second casting 64 and a cover plate it with a flexible diaphragm Bl interposed between the parts 54 and B4 and with a larger flexible diaphragm 1l peripherally clamped between the parts I4 and It. The diaphragm 6l thus forms the top wall of the fuel chamber N and it is provided with a centrally disposed button 12 which engages the stem 14 of the fuel inlet valve 16. The valve is normally urged toward its seat 1l by means of a spring 80 disposed below the valve in the valve seat fitting BI.

The cast body element 44 together with the diaphragms tl and 10 defines a suction or vacuum chamber 82 which is maintained in communication with the air induction tube It of the engine by means of a pipe 44 having a terminal fitting l. which leads from a port Il located at the construction 2l of the venturi. The chamber I2 and the flexible diaphragm 1II are thus subject at all times to variations in suction produced at the Venturi throat by adjustment of the throttle 22 or the choke 24. Thus, in starting the engine with the choke substantially closed, a high vacuum is produced which pulls strongly against the diaphragm 1li drawing it downwardly in the chamber l2. A pin IB is clamped to the center of the diaphragm 10 and projects downwardly therefrom into engagement with a small hollow shell 92 secured to the upper side of the diaphragm 6l by the button 12. Thus the downward movement of the diaphragm 1l is transmitted by the pin ll to the button 12 and to the valve stem 14, forcing the valve open in opposition to its spring Il and permitting the liquid fuel supplied under pressure by the pump l2 to flow from the orifices I4 into the chamber It and thence by way of the the engine and as the choke is opened admit- .f ting air, a more correct mixture for continued operation is supplied. The diaphragm 1l is readily responsive to the suction produced at the Venturi throat 20 because the upper side of the diaphragm is exposed to atmospheric pressure through the constantly open vent $4 in the top wall Il of the fuel control device.

It will be noted that the suction applied to the chamber l2 will act upwardly upon the flexible wall or diaphragm Il as well as downwardly upon the diaphragm 1l, but that because of the larger area of the diaphragm 1l, the net result will be a force in the downward direction. This excess force of the suction applied through the diaphragm 10 is sufncient to overcome the force of the fuel pressure acting upwardly against the diaphragm Il in a direction to permit the fuel inlet valve 1l to close. If the fuel pressure increases, this valve 14 will move toward closed position reducing the rate of flow, and if the fuel pressure is lowered, the valve 1l will open wider, increasing the flow rate. The effects of pressure variations at the fuel pump are thus neutralized, and the final rate oi' fuel now is determined by the adjusted position of the diaphragm 10 in response to the suction created by air now in the induction tube II. Y

Fig. 4 shows a spring Illreacting between the diaphragm 10 and a flange disc |02 carried on the end of an adjusting screw Il4 which is threaded into a boss III formed in the top wall I4. The valve control mechanism would function as described without the spring Ill but this spring is supplied to counteract or balance the spring Il which urges the valve 1l toward its seat. The balancing pressure furnished by the spring Ill may then be varied by means of the screw ll4 so as to provide the desired adjustment in the effective strength of the spring I4 for seating the valve and this adjustment may be maintained by means of a lock nut III on the screw |44.

While there is shown and described herein certain structure embodying the invention, it is to be understood that the invention is not limited thereto or thereby but may assume numerous other forms and includes all modifications. variations and equivalents coming within the scope of the following claims:

I claim:

1. In a charge forming device of a multiple outlet type which mixes a metered quantity of fuel duces a temporarily rich mixture for starting with air immediately adjacent the several outlets, the combination comprising an intake air manifold having an atmospheric opening and a plurality of outlet openings, said air manifold having a Venturi section therein to form a flow meter, a throttle valve downstream of said venturi so that actuation of said throttle valve controls the air delivery rate from all of said outlets while the pressure at said venturi is a function of the flow rate through said manifold and is independent of the pressure prevailing in said manifold downstream of said throttle valve. said manifold having a plurality of openings through the wall thereof each disposed immediately adjacent one of said outlets, a plurality of fuel nozzles each disposed adjacent to and in axial alignment with one of said openings and so disposed as to project jets of fuel from said nozzles through the intervening free space and through said openings and into said manifold immediately adjacent each of said outlets, means forming a second manifold enclosing the separate spaces between each of said nozzles and its associated opening, said second manifold having a connection to said first manifold at a point upstream of said throttle valve, and means including control means responsive to the preslsure at said venturi to supply said nozzles with fuel at a pressure which is a function of thel Venturi pressure.

2. The combination called for in claim 1 in which said openings are so proportioned as to supply a ilxed minimum flow of air from said outlets.

3. A charge forming device having the combination called for in claim 1 and an air filter connected to the atmospheric opening of said air intake manifold whereby said air cleaner serves to remove dust particles and the like from the air stream passing through said air intake manifold and through said second manifold.

4. In a charge forming device for a multiple cylinder combustion engine of the type which mixes a metered quantity of fuel with air immediately adjacent the several engine intake ports, the combination comprising an intake air manifold having an atmospheric opening at one end and a plurality of outlet openings adapted to communicate with the individual engine ports, said air manifold having a Venturi section therein to form a flow meter, a throttle valve downstream of said venturi so that actuation of said throttle valve controls the air delivery rate from all of said outlet openings while the pressure at said venturi is -a function of the flow rate through said manifold and is independent of the pressure prevailing in said manifold downstream of said throttle valve, said manifold having a plurality of openings through the side wall thereof each disposed immediately adjacent one of said outlet openings, a plurality of fuel noze zles each disposed adjacent to and in axial alignment with one of said openings and so disposed as to project jets of fuel from said nozzles through the intervening free space and through said openings and into said manifold immediately adjacent each of said outlet openings, said openings being so proportioned as to supply an appropriate flow of air to said ports under idling conditions of said engine, means forming a second manifold enclosing the separate spaces between each of said nozzles and its associated opening, said second manifold having a connection to said first manifold at a point upstream of said throttle valve, and means including control means responsive to the pressure at said venturi to supply said nozzles with fuel at a pressure which is a function of the Venturi pressure.

JOI-IN H. LESLIE, II.

REFERENCES crrnn The following references are of record in the le of this patent:

UNITED STATES PATENTS Mennesson Jan. 1. 1946 

